Gun



G. M. M CANN July 1-2, 1932.

GUN

Filed March 13, 1951 INVENTOR. Gear 2 M-I"I' Eann BY ATTORNEY Patented July 12, 1932 PA ENT GEORGE M. MCCAINN, or NEW CASTLE, DELAWARE Application filed March 13, 1931. Serial misaa ise.

(GRANTED UNDER THE AC T OF MARCH 3, 1883, AS AMENDED APRJELBO, 1928; 370 G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relatesto improvement in guns.

A recent development in the construction of guns resides in the provision of a loose tube or liner, that is, one in which a radial play space provided between the tube and jacket 1s taken up in firing and is restorable after firing and one in which the tube is free to ex-- pand and contract longitudinally.

There are now on hand a large number of guns that are to be remodeled to include a loose tube. In these guns the tube was inserted in the jacket from the front and secured by shrinking and usually in addition by a locking sleeve at the forward end of the i .20 acket.

In the present invention it is proposed to remove the shrunk tube and replace it with a loose or removable tube insertable from the rear of the jacket.

In order to allow for free longitudinal expansion and contraction it is necessary to secure the tube at the rear and in the present invention it is proposed to provide a simple and elfective securing means which may be conveniently held in place by the breech block operating shaft.

To this and other ends the invention consists in the construction, arrangement and combination of elements described hereinafter and pointed out in the claims forming a part of this specification.

A practical embodiment of the invention is illustrated in the accompanying drawing, wherein:

Fig. 1 is a longitudinal sectional view of a gun having a removable tube secured in the improved manner.

Fig. 2 is an enlarged sectional view through the securing means.

.Fig. 3 is a view in rear elevation of the gun, parts being in section.

F 4 is a sectional view on the line 14 of Fig. 3.

Referring to the drawing by numerals of reference There is shown a gun consisting of an internally cylindrical jacket 5, an externally tapered tube 6 freely insertable in the jacket from the rear and having a projecting unsupported forward portion 6a,aand a breech ring 7 threaded on the jacket in the usual manner. The breech ring carries a vertically sliding block 8 actuated in opening and closmg by a shaft 9 mounted in the breech ring and having a handle 9a.

As seen most clearly in Fig. 2, the outer, diameter of the tube is less than the inner diameter of the jacket to establish a radial play space l0between the tube and jacket. The amount of radial play space increases from rear to front and as a consequence insertion and withdrawal of the liner is facilitated. In this type of gun the powder pressure acts in firing to dilate the tube into contact with the jacket but the play space .is re stored when the powder pressure is no longer present. i

1 Since the tube is loosely mounted in the jacket and would be free to move rearward- H 1y upon inclination ofthegun there is pro- 7' vided a securing means consisting of a crosspin 11 inserted in an aperture in the breech ring and in atangential groove 12 in the tube. The groove is slightly larger than the, crosspin the clearance 13' corresponding to the radial play space 10, and also permitting of slight longitudinal movement of the tube relative to the jacket. =The longitudinal *factor of theclearance 13 is allowed for as shown in Fig. 3, so that when the tube sets 13 backs against the cross-pin, it will be substantially flush with the forward wall 14 of the breech block opening i n the breech ring.

The cross-pin is located as far tothe rear as possible so as to. permit longitudinal ex-eo pansion and contraction of the tube when in action. As seen in-Fig; 1 the cross-pin is positioned substantially directly above the breech block actuating shaft 9. The shaft 9 or the handle an thereon, whichever is the "96 more convenient for the purpose of removal,

is utilized to .carry a retaining member 15 for holding the cross-pin in place. ,As specifically shown the member 15 is in the form of a lug-integral with the shaft 9 andalso l ibreech ring'and loosely engaging, the tube.

liner relative to the jacket. 22-22 are provided on the liner between the shoulders 20 and 21 of'the jacket and by engaging in key ways 23 in the jacket hold the serving to anchor the usual return chain 15a. In order to reduce the size of the retaining member, the cross-pin 11 is provided with a depending tang 1111 which is disposed in a recess 16 in the breech ring and held therein by the overlying retaining member 15. When it is desired to insert or remove the cross-pin it is only necessary to remove the retaining member 1-5. clear of the tang 11a and this may be done by withdrawing it or rotating it depending on the particular character of the mounting, In any event the task will be a simple one that may b'equickly performed. v j

In those guns where the operating shaft is not present, for examplein guns using separate loading ammunition and a screw breech block, theretaining member 15 would be attached to the breech ring. 7 c

,As seen :most clearly in Fig. 3, the opening 17 provided in the breech ring to permit insertion of. a round of ammunition is made of "sufficient size. to permit passage of the tube.

The rear end of the liner is formed with oneor more collars, two being shown and designated 18 and 19. -These collars abut against annular shoulders 20 and 21 in the jacket and prevent forward movement of the Opposite keys liner against rotational movement relative to the jacket.

'By increasing the radial play space-'10 from rear to front it is possible to makethe invterior of the packet cylindrical and only the liner need betapered. In so far as this feature is concerned it is not dependent on the particular type of retaining means.

I claim. V v I 1 1. A gun'comprising a jacket, a tube within the jacket, the outer diameter of-the tube being less than the inner diameter of the jacket to establish a play space,-a breech ring on the jacket, a breech block in the breech ring, a block operating shaft carried by the "breech ring, across-pin insertable in the breechring above the shaft and loosely engaging the tube, and means carried by the shaft for retaining the cross-pin.

A gun-comprising a jacket, atube within the jacket, the outer diameter of. the tube being less than the inner diameter of the jacket to establish a play'space, a breech ring on the jacket, a. cross-pin insertable 'in the breech ring and loosely engaging thetube,

and means for retaining the cross-pin.

3. A gun comprising a jacket-,a tube within the jacket, the outer diameter. of the tube 7 jacket to establish aiplay space, a breech ring on "the j acket, a :cross-pin insert-able in the diameter of the outer member, a cross-pin insertable in the outer member and loosely engaging the tube adjacent its rear end.

A gun; comprising a tapered tube, a j acket extending over the rear part of the tube, theouter diameter of the tube beingless than the inner diameter; of the jacket whereby the tubeisinsertable in the jacket from the rear, and across-pin tangentially engaging the rear end ofthe tube to. hold the tube in place.

7 A gun comprising an internally cylin- .drical jacket and an externally taperedtube insertable in the jacket, the outer diameter of theitube being less. than the inner diameter of the jacket. 7 i

' GEORGE M. McCANN.

being less than the inner diameter'fof the 

